Adapter for electro-coalescer insulated electrodes with metal sealing for electrodes

ABSTRACT

Electro-coalescer systems herein may include a vessel, a base plate separating a process chamber and an electric enclosure, rod-shaped ceramic insulated electrodes, and a sealing assembly. An end of the electrodes is located within the electric enclosure. The electrodes traverse respective through-holes of the base plate into or through the process chamber, where a second portion is supported by a spacer, configured to maintain a position of the electrodes while allowing fluid passage. The sealing assembly forms a seal between the through-holes and the rod-shaped insulated electrodes, preventing fluid traversing from the process chamber into the electric enclosure. The sealing assembly may include: a metal fitting disposed around the rod-shaped insulated electrode; metal o-rings; metal seats; and a closing nut. The metal fitting has a coefficient of thermal expansion similar to that of the ceramic insulator, thereby preventing breakage of the electrodes during use.

BACKGROUND OF DISCLOSURE Field of the Disclosure

Embodiments disclosed herein relate generally to electro-coalescers.More specifically, embodiments herein relate to attachment of rod-shapedinsulated electrodes within an electro-coalescer vessel.

Background

From the electrical, chemical and thermal point of view, ceramics, suchas alumina, are the most suitable insulating materials for electrodesused in electrostatic-coalescers. Likewise, from the mechanical andprocess performance point of view, long rods or tubes are the mostsuitable geometries for insulated electrodes used in electro-coalescers.

As described in WO2018/153491, for example, a long ceramic tubeelectrostatic-coalescer electrode design may accommodate a longelectrical conductor in its interior. The internal conductor may beconnected to a power source, and the ceramic tube provides the requiredelectrical insulation and process sealing. However, such constructionposes major technical challenges.

As one example of a technical challenge, the coefficient of thermalexpansion of most metals, including suitable conductive metals, likecopper, is vastly different from that of ceramics, like alumina.Therefore, the temperature difference to which the electrodes aresubjected during their service life can easily cause the electrodes tofail structurally, which can result in process fluid leakage, andelectrical short-circuit, forcing the operation to stop.

As another example of a technical challenge, the high stiffness ofbrittle ceramics like alumina require the electrode construction andinterface s to be either flexible or be manufactured and assembled withthe highest level of precision. In a rigid construction, any smallmisalignment between the electrode and its interfaces with the equipmentcan result in structural failure of the electrodes, such asmisalignments arising during assembly, transportation, installation, orduring service as a result of vibrations and/or thermal and/or pressurecycling.

Further technical difficulties arise due to material discontinuities inthe ceramic tubes, such as voids and bubbles. These voids and bubblescan considerably increase power losses and result in maloperation and/orpremature failure of the equipment. Moreover, power losses may result inthe process fluid being heated beyond desirable limits, potentiallycausing destabilization of the process fluid as more gas may come out ofsolution.

Air pockets or gaps subject to the electric field inside of theelectrode can also considerably increase power losses and result inmaloperation and/or premature failure of the equipment. In practice,such air pockets and gaps can appear between the conductor inside of theelectrode assembly and the inner wall of the ceramic tube. Such gaps mayeven be left there on purpose, in order to leave clearance betweenmaterials with difference in coefficient of thermal expansion, therebypreventing structural failure of the electrode due to thermal variationsduring the lifespan of the unit.

Metallic parts in contact or in the vicinity of the ceramic tube presentfurther challenges, as these may locally but drastically intensify theelectrical stress over the ceramic insulation. This is particularly truewhere the geometry of the metal parts is rough or contains sharp edgesthat intensify the electric field over the ceramic material.

SUMMARY OF THE DISCLOSURE

Embodiments herein are directed toward electro-coalescers using longrod-shaped ceramic-insulated electrodes, where the configuration of thecoalescer and electrode, more specifically the attachment between theprocess vessel and the insulated electrode, are designed to address theabove-noted challenges. Moreover, the construction described herein isvery simple, robust and cost-effective for constructions intended forcommercial applications.

In one aspect, embodiments disclosed herein relate to anelectro-coalescer system. The electro-coalescer system may include: avessel, a base plate, one or more pipes, one or more rod-shapedinsulated electrodes, and a sealing assembly. The vessel may include avessel having a fluid inlet and a fluid outlet, between which is defineda process chamber. The base plate separates an electric enclosure fromthe process chamber. The one or more pipes fluidly connect the fluidinlet and the fluid outlet, and the one or more rod-shaped insulatedelectrodes each include a conductor disposed within a ceramic insulator.

A first end of the one or more rod-shaped insulated electrodes may belocated within the electric enclosure. The one or more rod-shapedelectrodes may traverse respective through-holes of the base plate andextend through at least a portion of the one or more pipes. A secondportion of the one or more rod-shaped electrodes is supported by aspacer, the spacer being configured to support and maintain a positionof the one or more insulated electrodes while simultaneously allowingfluid passage.

The sealing assembly may be configured to form a seal between thethrough-holes and the rod-shaped insulated electrodes, preventing fluidfrom traversing from the process chamber into the electric enclosure.The sealing assembly may include: a metal fitting disposed around therod-shaped insulated electrode; one or more metal o-rings; metal seats;and a closing nut. The metal fitting may have a coefficient of thermalexpansion similar to the coefficient of thermal expansion of the ceramicinsulator, thereby preventing breakage of the rod-shaped insulatedelectrodes during use, as may result from expansion of the components atoperating conditions.

In some embodiments, the metal fitting may have a coefficient of thermalexpansion within 1% of the coefficient of thermal expansion of theceramic insulator. In other embodiments, the metal fitting may have acoefficient of thermal expansion the same as the coefficient of thermalexpansion of the ceramic insulator.

The interface between the metal seat and the base plate may containfeatures to prevent the rotation of the electrode assembly and/or themetal o-rings while tightening the closing nut.

The rod-shaped insulated electrode may include a monolithic ceramic tubethat is void- and bubble-free. An inner wall of the monolithic ceramictube may be plated with a conductive metal, in some embodiments. And, anoutside wall of a conductive tubular sleeve may be in electric contactwith the conductive metal plating.

The rod-shaped insulated electrode, as noted above, may be a monolithicceramic tube. The monolithic ceramic tube may have an open end and aclosed end, and the closed end may extend a distance from an end of thetube. In some embodiments, the spacer may be located along the distanceof the closed end.

In some embodiments, the ceramic insulated electrode rods may be formedfrom alumina. The metal fitting may be formed from titanium. The spacermay be metallic. The metal o-rings, the metal seats, and the base platemay be made of a material different than that of the metal fitting insome embodiments.

Each through-hole of the base plate may include a threaded portionextending from the electrical enclosure side and terminating proximate afirst shoulder intermediate the electrical enclosure side and theprocess chamber side of the base plate. Each through-hole may alsoinclude a first longitudinal portion extending from the first shoulderto a second shoulder, as well as a second longitudinal portion extendingfrom the second shoulder to the process chamber side of the base plate.A first metal seat of the sealing assembly may be disposed proximate thefirst shoulder, a second metal seat of the sealing assembly may bedisposed proximate the second shoulder, and the first and second metalseats may each include a concave portion configured to mate with aconvex portion of the metal fitting.

In some embodiments, the first metal seat may include a shoulderconfigured to interact with the first shoulder of the through-hole suchthat longitudinal movement of the first metal seat along the firstlongitudinal portion is limited. The metal o-rings may form a sealbetween a metal fitting, one of the metal seats, and the through-hole.

In some embodiments, the base plate through-holes may be disposed at anangle from perpendicular, relative to a face of the base plate. Asupport hole of the spacer may also be disposed at a similar angle fromperpendicular. In such embodiments, the electrode rods may likewise beinstalled such that they are disposed at an angle through the processchamber.

In other aspects, embodiments disclosed herein are directed towardsealing assemblies for use with rod-shaped electrodes, and processes forseparating fluids, such as emulsions, using an electro-separatoraccording to embodiments described herein.

Other aspects and advantages will be apparent from the followingdescription and the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a simplified diagram of a coalescer system according toembodiments herein.

FIG. 2 and FIG. 3 illustrate a cross-sectional view of a sealing systemuseful with coalescer systems according to embodiments herein.

FIGS. 3A, 3B, and 3C illustrate cross-sectional views of sealingelements useful with coalescer systems according to embodiments herein.

FIGS. 4A, 4B, and 4C are cross-sectional views of a coalescer systemaccording to embodiments herein.

FIG. 5 is a peripheral view of a spacer useful with coalescer systemsaccording to embodiments herein.

FIG. 6 is a simplified diagram of a coalescer system according toembodiments herein.

DETAILED DESCRIPTION

Embodiments disclosed herein relate generally to electro-coalescers.More specifically, embodiments herein relate to electro-coalescershaving rod-shaped insulated electrodes and to the attachment of therod-shaped insulated electrodes within an electro-coalescer vessel.

Electro-coalescers according to embodiments herein may be used toseparate a process fluid, such as a fluid comprising a dominant phaseand a tight emulsion of at least a second, undesirable phase termed thedispersed phase. There may be multiple dispersed phases. Treatment ofthe process fluid may be performed in an electro-coalescer according toembodiments herein. After treatment, the fluid may have the same overallcomposition, but the droplets of the dispersed phase(s) have coalescedinto larger droplets. These larger droplets are much easier to separatevia conventional means, such as gravity or centrifugal separation, asthe larger coalesced droplets may settle or separate faster due toincreased mass.

The electro-coalescer may be applied to any fluid system where thespecific resistance of the dominant phase is larger than about 10⁷ Ohm*mand where the electric permeability of the dominant phase and thedispersed phase(s) are different. For example, the size of waterdroplets in hydrocarbon liquid or gas streams may be enlarged by theelectro-coalescer to more efficiently remove water from the liquid or todry the gas.

Electro-coalescer systems according to embodiments herein may be astand-alone unit operation, receiving a feed from upstream anddischarging a coalesced product stream for further processingdownstream, such as in a gravity settler. In other embodiments,electro-coalescer systems according to embodiments herein may beintegral with a gravity settler, such as described in WO2018153491 (FMCSeparation Systems By).

The electro-coalescer may include a vessel or outer shell having a fluidinlet, for receiving a fluid to be treated including a dispersed phaseof a given droplet size, and a fluid outlet, for discharging a treatedfluid that has an increased droplet size. Between the fluid inlet andoutlet is a process chamber having one or more pipes fluidly connectingthe fluid inlet and the fluid outlet. The pipes may traverse, forexample, from an inlet head of the vessel to an outlet head of thevessel, the pipes being arranged and supported by a tube sheet or otherstructures. The inlet and process chamber are configured to direct flowfrom the inlet, through the pipes, and to the outlet.

The electro-coalescer may also include a base plate separating anelectric enclosure from the process chamber. One or more rod-shapedinsulated electrodes, including a conductor disposed within a ceramicinsulator, are disposed in the vessel/process chamber, and may extendfrom inside the electric enclosure, through the base plate, and into orthrough the pipes. In this manner, the fluid to be treated may flowthrough the pipes in an annular region surrounding the electrode, incontact with an electric field generated by the electrodes, to result incoalescence of the dispersed phase.

In some embodiments, a first end of the one or more rod-shaped insulatedelectrodes is located within the electric enclosure. The electricenclosure may be, for example, proximate the inlet end or the outlet endof the process chamber. The one or more rod-shaped electrodes traverserespective through-holes of the base plate and through at least aportion of the one or more pipes. In some embodiments, the one or morerod-shaped electrodes traverse respective through-holes of the baseplate and through the one or more pipes, extending into the outletchamber, for example.

The rod-shaped insulated electrodes may be held in place or supported bya sealing assembly in each of the respective through-holes. A secondportion of the one or more rod-shaped electrodes may be supported by aspacer. The spacer or spacers, for example, may be disposed within theprocess tubes, supporting an end of the electrode. In other embodiments,the spacer(s) may be disposed in the inlet or outlet end of the processchamber, supporting an end of one or more electrode.

The spacer(s) may be configured to support and maintain a position ofthe one or more insulated electrodes while simultaneously allowing fluidpassage. For example, the spacers may include a support structureincluding a through-hole for receiving an end of the electrode and oneor more fluid passages. The spacers are described in more detail below,and may be metallic or a ceramic.

The sealing assembly may be configured to form a seal between thethrough-holes and the rod-shaped insulated electrodes, preventing fluidfrom traversing from the process chamber into the electric enclosure.The sealing assembly, described further below, may include a metalfitting disposed around the rod-shaped insulated electrode, one or moremetal o-rings, metal seats, and a closing nut, for example.

The metal fitting surrounds the insulated electrode, and is configuredto form a metal-to-ceramic insulator seal. The metal fitting may have acoefficient of thermal expansion similar to the coefficient of thermalexpansion of the ceramic insulator. The present inventors have foundthat by including a metal fitting having a coefficient of thermalexpansion similar to that of the ceramic insulator, the system integritymay be maintained, with essentially no breakage of the electrodes as aresult of thermal expansion of the system proximate the base plate.Similar coefficients of thermal expansion are defined herein as within3% of each other (|electrode−metal fitting|/electrode). In someembodiments, the metal fitting may have a coefficient of thermalexpansion within 2% or within 1% or within 0.5% of the coefficient ofthermal expansion of the ceramic insulator. In other embodiments, themetal fitting may have a coefficient of thermal expansion the same asthe coefficient of thermal expansion of the ceramic insulator.

In some embodiments, the ceramic insulator is alumina and the metalfitting is formed from titanium. Other ceramic-metal pairings may alsobe used. It is additionally noted that various grades of alumina mayhave different coefficients of thermal expansion; titanium ormixtures/alloys of titanium and other metals may also have coefficientsof thermal expansion that encompass a range of values. As noted above,the coefficients of thermal expansion of the materials used should besimilar, so as to provide the benefits described herein.

The metal o-rings, the metal seats, and the base plate may be made of amaterial the same as or different than that of the metal fittings. Asnoted above, it has been found that the properties of the metal fittingsare a controlling factor. While it would be desirable to have an overallsystem having similar coefficients of thermal expansion, cost and otherdesign factors may favor the matching of the coefficient of thermalexpansion of only the metal fitting to that of the ceramic insulatorused in the electrode.

For installation of the rods and to form the seal using the sealingassembly, each through-hole of the base plate may include a threadedportion extending from the electrical enclosure side and terminatingproximate a first shoulder intermediate the electrical enclosure sideand the process chamber side of the base plate. The through-holes mayalso include a first longitudinal portion extending from the firstshoulder to a second shoulder, and a second longitudinal portionextending from the second shoulder to the process chamber side of thebase plate. A first metal seat may be disposed proximate the firstshoulder, and a second metal seat may be disposed proximate the secondshoulder. Installation order of the sealing assembly, from the electricenclosure side to the process chamber side, may thus be: closing nut,first metal seat, first metal o-ring, metal fitting, second metalo-ring, and then second metal seat.

During installation, the closing nut may push the sealing assembly intothe through hole such that the second metal seat abuts the secondshoulder. The second metal o-ring may thus form a seal between the firstlongitudinal portion, the second metal seat, and the metal fitting.Rotation of the closing nut may also result in the first metal seatmoving closer to the second metal seat, forcing the metal fitting intosealing engagement with the ceramic insulator rod, and where the firsto-ring may form a seal between the first longitudinal portion, the firstmetal seat, and the metal fitting. The first and second metal seats eachinclude a concave portion configured to mate with a convex portion ofthe metal fitting, providing for a metal-to-metal seal as well as tofacilitate movement of the component parts when the closing nut isengaged.

To prevent over-tightening of the sealing assembly, the first metal seatmay include a shoulder configured to interact or engage with the firstshoulder of the through-hole, such that longitudinal movement of thefirst metal seat along the first longitudinal portion is limited. Inthis manner, the desired sealing of the ceramic insulator rods withinthe through-holes may be effectively formed while avoiding breakage ofthe ceramics.

In some embodiments, the sealing assembly may include an interfacebetween the metal seat and the base plate that contains features toprevent the rotation of the electrode assembly and/or the metal o-ringswhile tightening the closing nut. Rotation of the components may putundesired stress on the ceramic insulator rod, and thus rotationpreventing features may provide another means to limit or eliminateundesired breakage of the electrodes during assembly of the coalescersystem.

The rod-shaped ceramic insulated electrode may be formed as a monolithicceramic tube. Preferably, the monolithic structure is void- andbubble-free. An inner wall of the monolithic ceramic tube may be platedwith a thin layer of a conductive metal, such as copper. The conductivemetal layer may be thin enough to prevent mechanical damage of theceramic tube, the plate itself, or detachment of the two componentsduring service due to thermal variations. The conductive metal layer mayalso be thick enough to keep the electrical resistance along theelectrode sufficiently low.

An outside wall of a conductive tubular sleeve may be in electriccontact with the conductive metal plating. For example, an inner copperlayer of the ceramic tube may be in electrical contact with a conductivewire-braided tubular sleeve. In some embodiments, the conductive tubularsleeve may be in electric contact with the metal layer plated on themonolithic ceramic tube along the entire length of the inner surface ofthe ceramic tube.

The rod-shaped ceramic insulated electrode, as noted above, may be amonolithic ceramic tube. The tube may have an open end, a tubularsection, and a closed end. The open end may allow for installation ofthe conductive tubular sleeve within the ceramic tube, as well as forelectrical connection of the conductive sleeve to a power supply. Theclosed end of the tube may extend a distance from an end of the tubularsection. For example, the tubular portion of the ceramic rod mayterminate, but a solid end of the ceramic structure may continue for ashort distance. The thick ceramic end may thus provide for structuralintegrity of the ceramic rod, such as may be needed during installation,as well as for structural support of the rod within the spacer elementholding or supporting the end of the electrode within the coalescersystem. Thus, in some embodiments, the spacer may be located along thedistance of the closed end (i.e., between the terminus of the inner tubeand the end of the ceramic rod).

Referring now to FIG. 1 , an electro-coalescer system according toembodiments herein is illustrated. The electro-coalescer 10 may includean electric enclosure 12 and a process chamber 14. The electricenclosure 12 and the process chamber 14 may be separated by a base plate16.

A fluid inlet 18 may provide a flow of fluid into the inlet section 20,and the flow may be directed through one or more process tubes 22 to anoutlet end or outlet section 24. As illustrated, in some embodiments,the electro-coalescer may include long rod-shaped ceramic electrodes 26extending from the electric enclosure 12, through the base plate 16, andthrough the process tubes 22.

A first end 28 of the electrodes 26 may be supported by the base plate16, and a second end 30 of the electrodes may be supported by a spacer32. The electrodes may be electrically connected to a power source 34via electric cable and/or wiring 35, which may be disposed, at leastpartially, within a conduit 36. Additionally, the pipes or process tubes22 may be connected to a ground 38, such as via wiring or otherelectrical connections 39 between the process chamber shell 40 andground 38.

The first end 28 of the electrodes 26 is disposed through and supportedby the base plate 16. As discussed above, it is desirable to preventfluid flow into the electric enclosure, and thus a seal must be formedbetween the base plate 16 and the electrodes 26.

Referring now to FIGS. 2 and 3 , configurations of the electrode,support systems, and the seal assembly are illustrated. The rod-shapedceramic insulated electrodes 26, as noted above, may include amonolithic ceramic tube 50. An inner wall of the ceramic tube may becoated with a conductive metal layer 52, such as copper. Disposed withinthe metal coated ceramic tube may be a conductive tubular sleeve 54. Anoutside wall of the conductive tubular sleeve 54 may be in electriccontact with the conductive metal plating layer 52. For example, aninner copper layer 52 of the ceramic tube 50 may be in electricalcontact with a conductive wire-braided tubular sleeve 54. In someembodiments, the conductive tubular sleeve 54 may be in electric contactwith the metal layer 52 plated on the monolithic ceramic tube along theentire length of the inner surface of the ceramic tube 50.

The ceramic tube 50 of the electrode 26 may have an open end 60, atubular section 62, and a closed end 64. The open end 60 may allow forinstallation of the conductive tubular sleeve 54 within the ceramic tube50, as well as for electrical connection of the conductive sleeve 54 toa power supply 34 (FIG. 1 ), such as at end 55 of conductive sleeve 54.

The closed end 64 of the tube may extend a distance “d” from an end 66of the tubular section 62. For example, the tubular portion 62 of theceramic rod may terminate, but a solid end of the ceramic structure 50may continue for a short distance d. The solid end of the ceramicstructure may thus provide for the structural integrity and support ofthe ceramic rod, as discussed above. The end section 66 of the ceramictube 60 may be disposed within spacer element 32, holding or supportingthe end 66 of the electrode within the coalescer system. To provide thedesired support and structural integrity, the spacer may be locatedalong the distance d of the end section 64 (i.e., between the terminus66 of the inner tube and the end 70 of the ceramic rod). Restated, insome embodiments, the ceramic rod has an overall length such that theopen end 60 is disposed in the electric enclosure 12, while the solidend section 64 rests in the support structure 32.

A sealing assembly 70 may be provided to form a seal betweenthrough-holes 72 in the base plate 16 and the rod-shaped insulatedelectrodes 26. The seals desirably prevent fluid traversing from theprocess chamber 14 into the electric enclosure 12, as discussed above.The sealing assembly, as illustrated in the embodiments of FIGS. 2 and 3, may include a metal fitting 74 disposed around the rod-shapedinsulated electrode 26, one or more metal o-rings 76, a first metal seat78, a second metal seat 80, and a closing nut 82.

The metal fitting 74 may be formed from one or more component parts, andmay include a cylindrical inner surface 84. For example, the metalfitting 74 may be formed as a single ring having an inner diameter ofsimilar dimensions to that of the outer diameter of the ceramic rod. Inother embodiments, the metal fitting may be formed as a ring containingtwo, three or four independent sections, where compression of thesections forms a contiguous metal-to-ceramic seal between the metalfitting 74 and the ceramic rod 50.

An outer surface 86 of the metal fitting 74 may be spherical in shape.In some embodiments, the outer surface 86 of the metal fitting isspherical in shape proximate each longitudinal end of the fitting. Thespherical shape of the convex outer surface 86 may mate with a sphericalconcave inner surface 88, 90 of each of the first and second metal seats78, 80, respectively, as depicted in FIG. 3C.

Each through-hole 72 of the base plate 16 may include a threaded portion92. The threaded portion 92 may extend a distance from the electricalenclosure side 93 of the base plate 16, terminating proximate a firstshoulder 94. The threaded distance should be sufficient long so as toallow the closing nut 82 to apply and hold a force on the first metalseat 78. Shoulder 94 may be located intermediate the electricalenclosure side 93 and the process chamber side 95 of the base plate 16.The through-holes 72 may also include a first longitudinal portion 96extending from the first shoulder 94 to a second shoulder 98. Thethrough-holes 72 may further include a second longitudinal portion 99extending from the second shoulder 98 to the process chamber side 95 ofthe base plate 16. Installation order of the sealing assembly, from theelectric enclosure side 93 to the process chamber side 95 of the baseplate 16, may thus be: closing nut 82, first metal seat 78, a firstmetal o-ring 76, metal fitting 74, a second metal o-ring 76, and thensecond metal seat 80.

The closing nut 82, as noted above, when threaded into the through-hole72, may apply a force to the sealing assembly. Second metal seat 80 willthus abut second shoulder 98, preventing further movement of the sealingassembly through the through hole. At this point, continued rotation ofthe closing nut 82 will move the first and second metal seats 78, 80closer to one another, forcing the metal fitting 74 into sealingengagement with ceramic rod 50. The spherical surfaces 86, 88, 90provide for ease of movement between the component parts, allowing thefirst metal seat 78 to move further into the through-hole and resultingin sealing engagement of each component part of the sealing assembly.The metal fitting forms a seal against the ceramic rod, while the secondmetal o-ring forms a seal between the first longitudinal portion, thesecond metal seat, and the metal fitting, and the first o-ring may forma seal between the first longitudinal portion, the first metal seat, andthe metal fitting.

A shoulder 102 may be provided on an outer surface of first metal seat78. Shoulder 102 may be configured to engage with the first shoulder 94of the through-hole, such that longitudinal movement of the first metalseat 78 along the first longitudinal portion 96 is limited. The sizingof the component parts may thus be designed to provide the desiredsealing of the ceramic insulator rods within the through-holes 72 whileeffectively avoiding over-tightening of the seal assembly.

The sealing assembly may include an interface between the metal seat andthe base plate that contains features to prevent the rotation of theelectrode assembly and/or the metal o-rings while tightening the closingnut, such as a tongue-and-groove type relationship between the sealingelements. For example, a notch or circumferential groove 103 (FIGS. 3Aand 3B) in or along radial surface 104 of shoulder 94 may receive tongueor extension 105 (FIG. 3A) of first metal seat 78 located on an axialsurface of shoulder 102. Tongue or extension 105 may only partiallyencompass the circumference of the first metal seat shoulder 102. One ormore stops 107 may be located in circumferential groove 103. In thismanner, the extension may engage the notch, preventing rotation of thefirst metal seat 78 during rotation of the closing nut 82. Otherfeatures to prevent rotation of the electrode assembly and/or the sealassembly components may also be used.

Referring now to FIG. 4A-4C, cross-sections of the electro-coalescer areillustrated, were FIG. 4A illustrates cross-section A-A as shown in FIG.1 , FIG. 4B illustrates cross-section B-B as shown in FIG. 1 , and FIG.4C illustrates cross-section C-C as shown in FIG. 1 . As illustrated inFIG. 4A, inlet 18 may provide for a fluid flow into inlet section 20,flowing around the electrodes 26 traversing inlet section 20 (from thebase plate 16 to the process chamber 14, as illustrated in FIG. 1 ). Asillustrated in FIG. 4B, the process chamber 14 may have an outer shell40 through which are disposed multiple process tubes 22, through each ofwhich is disposed an electrode 26. Each of the electrodes may traversethrough a process tube 22 into outlet section 24, where an end 28 of theelectrodes may be supported by a spacer 32, as illustrated in FIG. 4C.The electrodes 26 may be disposed in support holes 41, while liquid flowmay be permitted through voids 42 formed in the structure of spacer 32.

FIG. 4C illustrates an embodiment where the electrodes extend fullythrough the process tubes 22. In some embodiments, such as where thereis only one process tube, or where the electrode terminates within aprocess tube, a spacer 32 such as illustrated in FIG. 5 may be used,where the electrode 26 is disposed within support hole 41 and liquidflow is permitted through voids 42.

Electro-coalescer systems according to embodiments herein may be astand-alone unit operation, such as illustrated in FIG. 1 . In such asystem, the electro-coalescer may receive a feed from upstream throughinlet 18. The fluid may then be treated (coalesced) during passagethrough process tubes 22. A coalesced product may then be recovered inoutlet end 24 and discharged via outlet 38 for further processingdownstream, such as in a gravity settler (not illustrated).

In other embodiments, electro-coalescer systems according to embodimentsherein may be integral with a gravity settler, such as illustrated inFIG. 6 . A separator according to embodiments as shown in FIG. 6 mayinclude main components such as a horizontal cylindrical vessel 701 andan electro-coalescer system 10 arranged within or partially within thevessel. The cylindrical vessel 701 features an inlet section 703,providing flow of a liquid into the electro-coalescer system 10. Thecylindrical vessel 701 may also include a main settling section 714,where settling of the coalesced droplets exiting electro-coalesceroutlet 24 may occur, and an outlet section 704, for recovery of theseparated phases. The vessel 701 may also include a gas outlet 706, anoil outlet 707 and a water outlet 708, arranged in the outlet section704. In some instances, when the fluid stream to be separated does notinclude significant amounts of a gaseous phase, the gas outlet 706 isnot required. The electro-coalescer assembly 10 may be similar to thatas described above with respect to FIGS. 1-5 .

As illustrated in each of FIGS. 1 and 6 , the rod-shaped electrodes arearranged concentric in relation to the fluid pipes. However, when thefluid pipes are arranged substantially horizontal during use, it may bebeneficial to have a little offset or some inclination of the rod-shapedelectrode with respect to the centerline of the fluid pipe (the fluidpipe functions as a grounding cell). In this manner, it is possible toaccommodate a free-water stream at the bottom of the electrode cell(i.e. the bottom of the fluid pipe of the electrode cell) withoutaffecting the electro-coalescence performance. Such an offset orinclination may help to achieve higher coalescence performance and helpprevent secondary droplet formation (re-emulsification). In variousembodiments, the pipes may be substantially horizontal while theelectrodes are inclined or declined, or the pipes may be inclined ordeclined while the electrodes are substantially horizontal. In yet otherembodiments, each of the electrodes and pipes may be inclined ordeclined. Up-flow or down-flow embodiments are also envisaged.

In instances where the electrodes are inclined or declined, they may bedisposed at an angle relative to the base plate 16 and the spacer(s) 32.In such instances, the through-holes 92 in base plate 16 and supportholes 41 of spacer(s) 32 may also be at the desired angle of inclinationor declination. In other words, while spacer 32 and base plate 16 mayeach be vertically disposed, the through-holes and other portionsinteracting with the electrode rods are formed at desired angles so asto result in proper disposal and support of the electrode rods.

The separator may also include a fluid/chemical injection system (notshown). Such a system may comprise an arrangement of spray nozzles,where each spray nozzle feeds an injection fluid/chemical at the inletto each cell of the electrocoalescer. The injection fluid/chemical canhave several functions, such as a chemical demulsifier, anti-fouling,fresh-water injection (e.g. for desalting applications), steam-injectionfor cleaning purposes, anti-corrosive fluid, etc.

The electrode assembly may use alternating current, high-voltage andhigh-frequency, to generate an intense electric field to polarize andrapidly coalesce dispersed water droplets in an oil-continuous phase.During operation, the strength of the electric field can be adjusted toreach an optimum value where water droplet-droplet coalescence ismaximized while secondary droplet formation is prevented. The largerwater droplets may separate much faster from the oil-continuous phase,such as in a main settling section 714 of an integral separator.

In use, a fluid flow to be separated will enter the inlet section 20 viathe fluid inlet 18, and thence into the annular space between the pipes22 and the electrodes 26, The liquid phase will partially separate intoa high-density phase, such as water, and a low-density phase, such asoil. In extreme case of extra heavy oil, the density of the phases maybe reversed. When passing through the pipes and electrodes of theelectrode assembly, water droplets dispersed in the oil phase willcoalesce and an improved phase separation is obtained in the separationzone of an integral gravity settler or a downstream settler.

As described above, embodiments disclosed herein provide anelectro-coalescer system having an improved support and sealing system,enabling use of long rod-shaped electrodes. The ceramic tubes of theelectrode may be a monolithic component, made of high purity ceramic,such as alumina. The ceramic tubes may be void- and bubble-free, and mayhave a thick-wall closed-end that greatly reduces electrical stress atthe interface with a metallic electrode spacer.

Further, the sealing assembly includes a metal fitting that has aspherical shape and may be made of titanium, which has a similarcoefficient of thermal expansion as the ceramic tube. This matching ofthe coefficients of thermal expansion may minimize thermal expansiondifference between the ceramic rod and the sealing assembly. Thespherical shape of the metal fitting or portions thereof, combined withthe metal o-rings and the metal seats provides the process seal, andserves as articulation of the electrode at its interface to the baseplate. The metal o-rings are soft and flexible, ensuring effectiveprocess seal despite surface irregularities or the use of a differentmaterial for the base plate. Together this gives the assembly therequired flexibility to prevent leakage or structural damage of theelectrode. The interface between the metal seat and the base platecontains features to prevent the rotation of the electrode assembly orthe metal o-rings while tightening the closing nut. Should such rotationnot be prevented, the likelihood of damaging the electrode assemblyand/or the metal o-rings would be very high.

The inner wall of the ceramic tube may be copper plated. The copperlayer may be thin enough to prevent mechanical damage of the ceramictube, the plating itself, or detachment of the two components duringservice due to thermal variations, but may also be thick enough to keepthe electrical resistance along the electrode sufficiently low.

The outside wall of a conductive wire-braided tubular-sleeve is inelectric contact with the inner copper layer, while its inside wall isin electric contact with a thin-wall copper pipe all along the ceramictube. This configuration provides the assembly with multiple advantages.For example, it prevents the presence of air in the electric field, asall air present in the electrode's interior is now at the sameelectrical potential. Further, it may diminish the electrical resistancethroughout the electrode, maximizing the efficiency of the system.Additionally, it provides a flexible mechanical connection, bothradially and axially, between the inner wall of the ceramic tube and thecopper pipe. And also very importantly, the presence of the copper pipemay greatly strengthen the electrode assembly, allowing it to beattached to the equipment at only two points, namely at the base plateinterface (articulated end) and at the electrode spacer interface(radially-fixed end).

While the disclosure includes a limited number of embodiments, thoseskilled in the art, having benefit of this disclosure, will appreciatethat other embodiments may be devised which do not depart from the scopeof the present disclosure. Accordingly, the scope should be limited onlyby the attached claims.

What is claimed is:
 1. An electro-coalescer system, comprising: a vesselhaving a fluid inlet and a fluid outlet, between which is a processchamber; a base plate separating an electric enclosure from the processchamber in the vessel; more than one pipes fluidly connecting the fluidinlet and the fluid outlet, more than one rod-shaped insulatedelectrodes, comprising a conductor disposed within a ceramic insulator;wherein: a first end of the more than one rod-shaped insulatedelectrodes is located within the electric enclosure, the more than onerod-shaped electrodes traverse respective through-holes of the baseplate and through at least a portion of the more than one pipes, and asecond portion of the more than one rod-shaped electrodes is supportedby a spacer, the spacer being configured to support and maintain aposition of the more than one insulated electrodes while simultaneouslyallowing fluid passage; a sealing assembly configured to form a sealbetween the through-holes and the rod shaped insulated electrodes,preventing fluid from traversing from the process chamber into theelectric enclosure, the sealing assembly comprising: a metal fittingdisposed around the rod-shaped insulated electrode; one or more metalo-rings; metal seats; and a closing nut; wherein the metal fitting has acoefficient of thermal expansion similar to the coefficient of thermalexpansion of the ceramic insulator.
 2. The electro-coalescer system asclaimed in claim 1, wherein the metal fitting has a coefficient ofthermal expansion within 1% of the coefficient of thermal expansion ofthe ceramic insulator.
 3. The electro-coalescer system as claimed inclaim 1, wherein the metal fitting has a coefficient of thermalexpansion the same as the coefficient of thermal expansion of theceramic insulator.
 4. The electro-coalescer system as claimed in claim1, wherein the interface between the metal seat and the base platecontains features to prevent the rotation of the electrode assemblyand/or the metal o-rings while tightening the closing nut.
 5. Theelectro-coalescer system as claimed in claim 1, wherein the rod-shapedinsulated electrode comprises a monolithic ceramic tube that is void-and bubble-free, and wherein an inner wall of the monolithic ceramictube is plated with a conductive metal, and wherein an outside wall of aconductive tubular sleeve is in electric contact with the conductivemetal plating.
 6. The electro-coalescer system as claimed in claim 1,wherein the rod-shaped insulated electrode comprises a monolithicceramic tube having an open end and a closed end, and wherein the closedend extends a distance from an end of the tube.
 7. The electro-coalescersystem as claimed in claim 6, wherein the spacer is located along thedistance of the closed end.
 8. The electro-coalescer system as claimedin claim 1, wherein the ceramic insulator comprises alumina and whereinthe metal fitting comprises titanium.
 9. The electro-coalescer system asclaimed in claim 1, wherein the spacer is metallic.
 10. Theelectro-coalescer system as claimed in claim 1, wherein the metalo-rings, the metal seats, and the base plate are made of a materialdifferent than that of the metal fitting.
 11. The electro-coalescersystem as claimed in claim 1, wherein each through-hole of the baseplate comprises: a threaded portion extending from the electricalenclosure side and terminating proximate a first shoulder intermediatethe electrical enclosure side and the process chamber side of the baseplate; a first longitudinal portion extending from the first shoulder toa second shoulder; and a second longitudinal portion extending from thesecond shoulder to the process chamber side of the base plate; andwherein a first metal seat is disposed proximate the first shoulder, asecond metal seat is disposed proximate the second shoulder, and whereinthe first and second metal seats each comprise a concave portionconfigured to mate with a convex portion of the metal fitting.
 12. Theelectro-coalescer system as claimed in claim 11, wherein the first metalseat comprises a shoulder configured to interact with the first shoulderof the through-hole such that longitudinal movement of the first metalseat along the first longitudinal portion is limited.
 13. Theelectro-coalescer system as claimed in claim 11, wherein the metalo-rings form a seal between the metal fitting, one of the metal seats,and the through-hole.
 14. The electro-coalescer system as claimed inclaim 1, wherein the base plate through holes are disposed at an anglefrom perpendicular, and wherein a support hole of the spacer is disposedat a similar angle from perpendicular.